The subject invention is directed generally to sinterable tapes utilized in the fabrication of unitized multilayer circuit structures, and is directed more particularly to a multiple sinterable tape array that is useful for high rate production of unitized multilayer circuit structures.
Hybrid multilayer circuit structures, also known as hybrid microcircuits, implement the interconnection and packaging of discrete circuit devices, and generally include a unitized multilayer circuit structure formed from a plurality of integrally fused insulating layers (e.g., ceramic layers) having electrical circuit patterns disposed there-between. The electrical circuit patterns comprise, for example, metallizations and passive components such as resistors and capacitors, and can be formed by thick film screen printing processes. Electrical interconnection of the electrical circuit patterns between the different layers is achieved with vias or holes appropriately located and formed in the insulating layers and filled with appropriate via fill material, for example by thick film screen printing, whereby the via fill material is in contact with predetermined metallization traces between the layers that extend over or under the vias. The discrete circuit devices (e.g., integrated circuits) are commonly mounted on the top insulating layer so as not to be covered by another insulating layer or on an insulating layer having die cutouts formed thereon to provide cavities for the discrete devices. Passive components such as capacitors and resistors can be formed on the same layer that supports the discrete devices, for example, by thick film processes.
Unitized multilayer circuit structures are commonly made pursuant to co-fired technology wherein a unitized multilayer circuit module is made from layers of sinterable insulating material (comprising for example a ceramic material) known in the art as "green tape". Generally, each of the green tape layers of a particular module is cut to size (i.e., "blanked") from a larger sheet or strip of unfired green tape, punched and screen printed to include a predetermined pattern of vias, interconnecting conductive traces, and electrical components such as resistors and capacitors. The individual screen printed green tape layers for a module are then stacked in the required order, and laminated together using a chosen temperature and pressure. The laminated structure is then fired at an elevated temperature. Such co-fired technology has been implemented with low temperature co-fired ceramic (LTCC) as well as with high temperature co-fired ceramic (HTCC).
Examples of low temperature co-fired processing can be found in "Development of a Low Temperature Co-fired Multilayer Ceramic Technology," by William A. Vitriol et al., 1983 ISHM Proceedings, pages 593-598; "Processing and Reliability of Resistors Incorporated Within Low Temperature Co-fired Ceramic Structures," by Ramona G. Pond et al., 1986 ISHM Proceedings, pages 461-472; and "Low Temperature Co-Fireable Ceramics with Co-Fired Resistors," by H. T. Sawhill et al., 1986 ISHM Proceedings, pages 268-271.
Known techniques for blanking and collating have included the use of hand pick and place equipment and robotic equipment. Such equipment is slow and costly, and moreover can process only one hybrid module at a time.